• Asian Pacific Journal of Cancer Prevention
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• 제17권1호
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• pp.255-259
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• 2016

Background: Reliable and validated instruments are needed in order to study the quality of life in myeloma patients. This study aimed to translate and explore the psychometric properties of the European Organisation for Research and Treatment of Cancer (EORTC) myeloma module (QLQ-MY20) in Iranian patients. Materials and Methods: Two hundred and fifteen patients with multiple myeloma (MM) were recruited from Imam Khomeini Hospital, Tehran. A standard forward-backward translation procedure was implemented. Participating patients were asked to complete the EORTC QLQ-C30 and the QLQ-MY20 three times, at study entry, after two weeks, and again after three months. Data were tested for the range of measurement, internal consistency, test-retest reliability, known group comparison, responsiveness and factor structure. Results: Mean age of the patients was 60.7 years. No floor and ceiling effects were seen for the QLQ-MY20. Cronbach's ${\alpha}$ was greater than 0.80 for all three multi-item scales (ranging from 0.82 to 0.93). All four scales had test-retest reliability of 0.85 or greater. Results of the confirmatory factor analysis that the hypothesized 3-scale measurement model of the QLQ-MY20. Moreover, the Persian version for the QLQ-MY20 differentiated between subgroups of the patients in terms of beta-2 microglobulin, fracture and performance status. The responsiveness of the QLQ-MY20 to change over time was confirmed within 3 months. Conclusions: the results of our study indicate that our Iranian version of the QLQ-MY20 is a feasible, reliable and valid questionnaire for assessing the condition-specific quality of life of patients with MM.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권4호
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• pp.330-343
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• 2016

This paper presents results of an experimental investigation of vortex-induced vibration (VIV) of a flexibly mounted and rigid cylinder with two-degrees-of-freedom with respect to varying ratio of in-line natural frequency to cross-flow natural frequency, $f^*$, at a fixed low mass ratio. Combined in-line and cross-flow motion was observed in a sub-critical Reynolds number range. Three-dimensional displacement meter and tension meter were used to measure dynamic responses of the model. To validate the results and the experiment system, x and y response amplitudes and ratio of oscillation frequency to cross-flow natural frequency were compared with other experimental results. It has been found that the higher harmonics, such as third and more vibration components, can occur on a certain part of steel catenary riser under a condition of dual resonance mode. In the present work, however, due to the limitation of a size of circulating water channel, the whole test of a whole configuration of the riser at an adequate scale for VIV phenomenon was not able to be conducted. Instead, we have modeled a rigid cylinder and assumed that the cylinder is a part of steel catenary riser where the higher harmonic motions could occur. Through the experiment, we have found that even though the cylinder was assumed to be rigid, the occurrence of the higher harmonic motions was observed in a small reduced velocity ($V_r$) range, where the influence of the in-line response is relatively large. The transition of the vortex shedding mode from one to another was examined by using time history of x and y directional displacement over all experimental cases. We also observed the influence of in-line restoring force power spectral density with $f^*$.

• 한국항공우주학회지
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• 제38권5호
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• pp.445-455
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• 2010

본 연구에서는 실제 로켓엔진 및 가스터빈용 연소기 내부의 열음향 불안정을 효과적으로 예측하기 위하여, 헬름홀츠 방정식과 시간지연모델을 이용한 3차원 유한요소법 해석코드를 개발하였다. 연소응답항에 의해 수치적으로 야기되는 비선형성은 반복법으로 선형화 하였으며, Arnoldi 방법을 사용하여 대용량 고유치 문제를 해석하였다. 해석결과인 복소각주파수와 음향 압력장을 통해 각 음향모드의 공진주파수, 진폭의 증폭/감쇠 여부 그리고 모드 형태를 예측할 수 있다. 이론해가 존재하는 두 가지 문제를 통해 출구 임피던스와 예혼합 화염이 종 방향 음향장에 미치는 영향에 대한 예측 정확도를 평가하였으며, 배플 유무에 따른 횡 방향 음향 모드의 주파수 변이를 상온 음향시험 결과와 비교/검증하였다.

• 한국강구조학회 논문집
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• 제21권6호
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• pp.609-618
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• 2009

본 연구에서는 다양한 설계조건 하에서 철골보의 내화시간을 평가할 수 있는 산정식을 열-구조 연성해석(fully coupled thermo-mechanical analysis)을 토대로 제안하였다. 본 연구에서 제안하는 산정식은 철골보의 화재거동에 미치는 주요 인자를 구조변수 및 열변수로 명시적으로 반영하므로 각 설계변수의 내화성능에 대한 영향을 설계자가 쉽게 정량적으로 파악할 수 있는 강점이 있다. 광범위한 변수해석을 수행하기에 앞서 실물대 화재실험 결과를 활용하여 본 연구의 열-구조 연성해석모델의 타당성을 검증한 후, 철골보에 붕괴처짐(run-away deflection)이 발생할 때까지 화재거동에 대한 각 변수들의 영향력을 검토하였다. 이러한 수치해석결과를 다양한 설계조건에서 철골보의 내화시간 예측에 활용할 수 있도록 다중선형회귀분석을 통해 통계학적으로 신뢰도가 높은 평가식을 제안하였다. 현행 사양설계기준에서의 활용법을 사례를 들어 예시하였고, 제시된 식으로부터 얻어지는 경제성과 장점을 입증하였다.

• Coupled systems mechanics
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• 제9권2호
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• pp.163-182
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• 2020

Coupled thermo-mechanical analysis of reinforced concrete slab at elevated temperatures from a fire accounting for nonlinear thermal parameters is carried out. The main focus of the paper is put on a one-way continuous reinforced concrete slab exposed to fire from the single (bottom) side as the most typical working condition under fire loading. Although contemporary techniques alongside the fire protection measures are in constant development, in most cases it is not possible to avoid the material deterioration particularly nearby the exposed surface from a fire. Thereby the structural fire resistance of reinforced concrete slabs is mostly influenced by a relative distance between reinforcement and the exposed surface. A parametric study with variable concrete cover ranging from 15 mm to 35 mm is performed. As the first part of a one-way coupled thermo-mechanical analysis, transient nonlinear heat transfer analysis is performed by applying the net heat flux on the exposed surface. The solution of proposed heat analysis is obtained at certain time steps of interest by α-method using the explicit Euler time-integration scheme. Spatial discretization is done by the finite element method using a 1D 2-noded truss element with the temperature nodal values as unknowns. The obtained results in terms of temperature field inside the element are compared with available numerical and experimental results. A high level of agreement can be observed, implying the proposed model capable of describing the temperature field during a fire. Accompanying thermal analysis, mechanical analysis is performed in two ways. Firstly, using the guidelines given in Eurocode 2 - Part 1-2 resulting in the fire resistance rating for the aforementioned concrete cover values. The second way is a fully numerical coupled analysis carried out in general-purpose finite element software DIANA FEA. Both approaches indicate structural fire behavior similar to those observed in large-scale fire tests.

• Journal of Korean Neurosurgical Society
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• 제56권3호
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• pp.224-229
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• 2014

Objective : To report long-term clinical and radiological outcomes of minimally invasive posterior cervical foraminotomy (MI-PCF) performed in patients with unilateral single-level cervical radiculopathy. Methods : Of forty-six patients who underwent MI-PCF for unilateral single-level radiculopathy between 2005 and 2013, 33 patients were included in the study, with a mean follow-up of 32.7 months. Patients were regularly followed for clinical and radiological assessment. Clinical outcome was measured by visual analogue scale (VAS) for the neck/shoulder and arm, and the neck disability index (NDI). Radiological outcome was measured by focal/global angulation and disc height index (DHI). Outcomes after MI-PCF were evaluated as changes of clinical and radiological parameters from the baseline. Mixed effect model with random patients' effect was used to test for differences in the clinical and radiological parameters repeat measures. Results : There were no complications and all patients had an uneventful recovery during the early postoperative period. VAS scores for neck/shoulder and arm improved significantly in the early postoperative period (3 months) and were maintained with time (p<0.001). NDI improved significantly post-operatively and tended to decrease gradually during the follow-up period (p<0.001). There were no statistically significant changes in focal and global angulation at follow-up. Percent DHIs of the upper adjacent or operated disc were maintained without significant changes with time. During the follow-up, same site recurrence was not noted and adjacent segment disease requiring additional surgery occurred in two patients (6%) on the contra-lateral side. Conclusion : MI-PCF provides long-term pain relief and functional restoration, accompanied by good long-term radiological outcome.

• Korean Chemical Engineering Research
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• 제49권3호
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• pp.372-380
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• 2011

촤-가스화 반응은 반응온도, 반응가스 부분압력, 시스템 총 압력, 입자크기 등 운전조건뿐만 아니라 촤의 화학적 조성 및 물리적 구조의 영향을 받는다. 본 연구에서는 두 종류의 역청탄 촤를 이용하여 반응온도 1,000-$1,400{^{\circ}C}$에서 $CO_{2}$ 가스화시 입자크기의 영향을 관찰하였다. 실험실 규모의 고정식 반응기를 이용하여 대기압 하에서 실험을 수행하였으며 반응가스인 $CO_{2}$(40 vol%)가 반응기에 공급되면 촤와 반응하여 CO를 생성하였다. 촤의 탄소 전환율을 측정하기 위하여 비분산적외선 방식의 CO/$CO_{2}$ 센서가 장착된 실시간 가스분석기를 이용하였다. 실험결과 동일한 온도에서 입자크기가 감소할수록 가스화 반응성은 증가하였으며 온도가 증가할수록 반응성에 미치는 입자크기의 영향은 더욱더 크게 증가하였다. 또한 반응성이 낮은 촤에서 입자크기의 영향은 다소 적게 나타났다. 입자크기와 석탄 종류는 반응모델에도 영향을 주었다. Shrinking core model은 반응성이 낮은 석탄을 잘 묘사했으며 반대로 Volume reaction model은 반응성이 높은 석탄을 잘 묘사하였다.

• 한국유통학회지:유통연구
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• 제15권3호
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• pp.111-137
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• 2010

본 연구는 서비스 시장에서의 지각된 품질과 개인가치간의 인과적 관계 및 고객의 인지욕구에 따른 온 오프라인상의 조절효과에 대해 실증분석하였으며 이를 통해 개인가치에 대한 서비스 전략과 마케팅 관리의 중요성을 제시하고 있다. 서비스 시장에서 서비스 제공자와 구매자간의 장기적 거래관계의 중요성이 크게 부각됨에 따라 관계구축 및 강화에 매우 중요한 역할을 하는 개인가치에 관한 연구는 학계뿐만 아니라 실무적으로도 고객관계관리의 관점에서 시사하는 바가 크다고 할 수 있다. 실증분석을 위해 대형마트(할인점)와 인터넷 쇼핑몰을 이용하는 고객을 대상으로 설문을 통해 데이터를 수집하였으며 온 오프라인의 비교분석을 통한 차이검증을 위한 인과적 구성모델에 대해 구조방정식 모델분석을 통해 가설검증하였다. 구성모델에 대한 분석결과 물리적 환경, 상호작용 품질, 그리고 결과품질로 구성된 지각된 품질은 안정적 삶, 사회적 인식, 사회적 통합으로 구성된 서비스 개인가치에 통계적으로 매우 유의한 정(+)의 영향을 미치는 것으로 나타났으며 집단간 차이효과분석을 통해서도 온 오프라인에 따른 조정효과는 온라인에서보다는 오프라인에서 더 유의한 것으로 나타났다. 그리고 온라인상에서의 서비스에 대한 인지욕구가 높을 때보다는 오프라인상에서의 서비스에 대한 인지욕구가 높을 때 개인가치에 더 유의한 영향을 미치는 것으로 나타났다. 마지막으로 본 연구의 구성모델에 대한 적합도 역시 수용할만한 수준인 것으로 나타났다.

• Journal of Korean Neurosurgical Society
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• 제46권5호
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• pp.479-483
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• 2009

Objective : A mouse model of spinal cord injury (SCI) could further increase our basic understanding of the mechanisms involved in injury and repair of the nervous system. The purpose of this study was to investigate whether methods used to produce and evaluate photochemical graded ischemic SCI in rats, could be successfully adapted to mice, in a reliable and reproducible manner. Methods : Thirty female imprinting control region mice (weighting 25-30 g, 8 weeks of age) were used in this study. Following intraperitoneal injection of Rose bengal, the translucent dorsal surface of the T8-T9 vertebral laminae of the mice were illuminated with a fiber optic bundle of a cold light source. The mice were divided into three groups; Group 1 (20 mg/kg Rose bengal, 5 minutes illumination), Group 2 (20 mg/kg Rose bengal, 10 minutes illumination), and Group 3 (40 mg/kg Rose bengal, 10 minutes illumination). The locomotor function, according to the Basso-Beattie-Bresnahan scale, was assessed at three days after the injury and then once per week for four weeks. The animals were sacrificed at 28 days after the injury, and the histopathology of the lesions was assessed. Results : The mice in group 1 had no hindlimb movement until seven days after the injury. Most mice had later recovery with movement in more than two joints at 28 days after injury. There was limited recovery of one joint, with only slight movement, for the mice in groups 2 and 3. The histopathology showed that the mice in group 1 had a cystic cavity involving the dorsal and partial involvement of the dorsolateral funiculi. A larger cavity, involving the dorsal, dorsolateral funiculi and the gray matter of the dorsal and ventral horns was found in group 2. In group 3, most of the spinal cord was destroyed and only a thin rim of tissue remained. Conclusion : The results of this study show that the photochemical graded ischemic SCI model. described in rats, can be successfully adapted to mice, in a reliable and reproducible manner. The functional deficits are correlated an increase in the irradiation time and, therefore, to the severity of the injury. The photothrombotic model of SCI, in mice with 20 mg/kg Rose bengal for 5 minutes illumination, provides an effective model that could be used in future research. This photochemical model can be used for investigating secondary responses associated with traumatic SCI.

• 수산해양기술연구
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• 제15권1호
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• pp.5-16
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• 1979

朴.李등 (1972)이 축양 시험을 할 때에는 축양조 이외에 소형의 예인조를 따로 썼으나, 예인조에서 축양조로 이송이 번거로우므로 업계에서는 축양조를 바로 예인하는 방법이 쓰이고 있다. 그러나, 축양조를 바로 예인하면 앞면의 망지가 뒤로 밀려서 축양조 내부의 용적이 작아지고, 또 예인중 축양조의 속도가 갑자기 느려지면 멸치는 유영 관성으로 말미암아 뒤로 밀린 망지 위로 올라가서, 비늘이 벗겨져서 폐사율이 높아진다. 이를 개량하기 위해 먼저 $\frac{1}{15}$크기의 모형 축양조를 만들어서, 회류수조에서 4가지 방식으로 예인시험을 실시하고, 그 중 합리적이라고 생각되는 2가지 방식을 다시 해상에서 실물시험을 실시하여, 실용상의 문제점을 규명함과 동시에, 축양조의 예인속도는 빠르게 하면서도 축양조 내부의 유속을 느리게 하는 방법도 고안했다